Pyrometer



Filed June 15, 1927 -nBlYlX- ULM ATTORNEYS.

Patented. sept. 17,1929

T OFFICE RoBEn'rc. PAIRMAN, oF BERKELEY, CALIFORNIA..

PYnoME'rER ,Appucatin med Juneis,

This invention relates to pyrometers and like instruments, andespecially to that type which depends upon the differential expansion oftwo elements for indicating temperatures. y

Pyrometers of the above character usually consist of acasing providedwith a dial which is' graduated into degrees, Fahrenheit or centigradeas the case may be, to indicate temperature.

The casing is provided with a tubular eX- 1 tension,preferablyconstructedof a metal having a comparatively high coetlicientof tube'is transmittedthrough a rod having a low coelicientv ofexpansion to a gauge movement, and this, in turn, actuates a pointer orindicator which swings over the graduated dial and thereby indicateslternperature'. A number of temperature indicating instruments embodyingthe above-elements and I mechanism have been constructed and used but'from a practical operating point 'of view have, in most instances,proven a failure, due to`the following reasons: Back lash,v and lostmotion has been encountered which could not be compensated; the linkandfgauge movements employed werediflieu-,lt to adjust; the expandingandfhQn'-expending elements employed would :deteriovrame ordisintegrate, when exposed to high temperatures, and their"coeiiicientof exten- L sion would gradually. change, causing ine-or,-V

rect temperature""readings to be indicated. The resultl istliattemperature indicating in'- s'tr'uments of this character have beenractically abandoned in favor -of electrlc or thermo-couple actuatedpyrometers.

(The object of the present invention Vis to generally improve andsimplify the construction and operation fof pyrometers of the characterdescribed (by vproviding eX- panding and non-expanding elements which 5will stand vhigh temperatures without ldanger of deterioration or changein their coefficient of expansion; [by providing a link and 'connectedgauge movement which'may be readily and easily-,adjusted by providing 0means for positively taking up all back expansion. The expandingmovement of the 1927. Serial No. 198,943.

lashgand lost movement; and furtherfby providinga'linkfand'gaugemovement which 1s sturdyfand substantial and reliable in op; eration?when subjected to different uses= The pyrometer is shown by way ofillustration inthe accompanying drawings, in whichj? C Fig. 1 is -afront view ofthe pyrometer,"l said View being partially in section andpar, i i tially broken away to show the operating mechanism. Y 2 is acentral, vertical, longitudinal section. Fig. 3 is a cross section,taken on line 3 3 of Fig. 1. y .y

Fig.'4 is an enlarged section pn line 4-4.- 0f. Fia'- 1- y .Referring tothe drawings in ldetail and f particularly Figs.- 1 and 2, A indicates acas ing, consisting of a bottom section 2 anda circular side wall 3;Projecting through the lower portion of the side wall 3,;as` at 4, is atubular extension 5, on the upper end ofy which is formed a head member6` and a combinationV bearing` and guide f?.y The tube 5, togeth .,ththe'head member is secured'to' the,v lsing in any suitable manner and,Jas V'here indicated, by meansl -of screws 8. -Securediin the lower endof the tubular ex- 30 tension 5 is a tube 9. AThe lower end of the tubeis closed by means of a pliig or the like indicated at'10, and mountedinteriorly ofvrthe tube and guided thereby is a rodll, the'function'ofwhich will be hereinafter described; Slidably mounted in the tubularvextension 5 is a plunger or connectingfrod 12. This plunger rests onthe upper end of the rod 11, andthe upper end-of the plunger ispivotally connected, .as at 13, with au. main, actuatinglever, generallyindicated vat v14:. This lever is pivotally mounted, as au15, in thebearing 7. The bearing is. slotted lengthwise to form a guidefor thelever 14, andthe center 'portion is 95 drilled to form a .guide for theplunger 12; thevupper end oilthe plunger being slotted, `as vat 16, (seeFig. 2) to straddle and connect with the main actuating lever 14.

Mounted within the casing'A is a gauge 100 movement, which is generallyindicated at B. This movement consists of a base plate '17 and a top'plate 18 which are interspacedwith relation to each other. by means ofs acing posts, such as indicated at 19. 'ournaled betweenA the plates isa `spindle I 20, and secured thereon is a small spur gear pinion 21whieh intermeshes with a segmental rack bar 22. This rack member 'ispivotally mounted, as vat 23,v between the plates'l? and 18 andisprovided with an adjustablelever extension 24 which is connected withthe main operating lever. 14 'through means of a4 link 25. l i

The spindle carries an ordinary pointer' or indicator hand 26 and thisis movable over a dial 27 which is graduated in degrees =Fahrenheit or'centiUrade-as particular uses may demand. T e gauge movement, generallyindicated at B, which has been more or less specifically described, is astandard movement and `no invention Ais claimed as .far as the specificstructure involved is concerned, The manner of mounting the movement,however, is new and.

this will be described in detail.

. By referring to Figs. 1, 2 and 3 it will be noted that one end of thebase,plate 17 is pivotally secured to the bottom section-2 of the casingby means of a screw or the like, such as indicated at4 28. The oppositeend of the base plate is secured to the bottom section 2 by means. of ascrew 29. The bottom section 2 is provided withan lelongated f'slot, asindicated at 30, where the screw '29'passes through, and it is thuspossible to Vswing' the entire gauge mcvement about thepivotal-connection 28. This is'important as 4it permits adjustment ofthe indicating handJ 26 with relation to. the graduated dial from a",oint exteriorally of the casing.. f

- lou'nted on the exterior or rear side of the I bottomsection 2 of thecasing is a pair of postsf.- such as 'indicated at 31 and 32. The post31 is adjustable'and the'post 32 is stationary as it is secured to thebottom section 2- of the casing by means of a screw l l33. liA" threadedrod 34 is secured Vat one end, as 'ati 35, to thepost The' oppositefendof the threaded rod extends through 'the post 32 and it carries/apair of adjusting st :rews 136' and 37.and 'a set or lock screw 38isprovided The pivotscrew 29 extends "lock nuts 39on its outer end.

through v`the post 31 and carries a pair of If. itis ldesiredtoadjustthe pointer"2 y with relation to thelgraduated gauge Ydialstance, if it is`desired to swing the gauge it is only necessary toloosen the set-screw 38 and the lock nuts 39 and one or the other of theadjusting-screws. 36 or v3 7. For in;y

iI movement" about the pivot 28 towards the left, screw 37 is sl'ackenedand screw 36 is .v f tightened. vThis willpull the block 3l, the '65screw 29 and-the gauge movementlongitudinally of the slot 30 towards theleftand as the main operating lever 14 and link 25 are stationary, itwill have the same eiect upon the segmental rack 22 as if it were swungabout its pivot towardsv the left-hand'side ofthe casing. In otherwords, the pinion 21, together with the spindle and the indieating hand26, will swing contraclockwise, and when the desired adjustment isobtained it will only be necessary to tighten the sev- -eral screws,lock nuts, and the adjustment will be maintained.

which depends upon several features, such as the distance between thepivots 13 and 15, the distance between the point 15 and the upperpivotal connection of the link 25, andl uthe position of the adjustablelever 24 with relation tothe-.pivotal point 23. The ratio or themovement, which depends upon vthese distances. can only be adjusted bychanging the position of the extension 24 or by changing the position4of the link 25 with relation to the main actuating lever 14. To permitsuch adjustment an adjustable plate 40 is employed.

This'adjustable plate 40 is slotted and it is secured-to the upper endof the main operating lever 14 by means of av pair of It is accordinglypossible-to if. itl is desired 'to adjasf the indicating A screws, suchas indicated at 41. Thev link 25 is pivotally secured to the upper endof the slotted plate, as at '42. By slackening the v screws 41 the plate40 maybe adjusted upfV wardly or downwardly onfthe lever 14 and thedistancebetween the points 15'and '42 may accordingly be adjusted,thereby increasing or decreasing the leverage'or ratio of the movement.x

A similar adjustment isV obtained by moving thev adjustable lever 24upwardlyv or.

downwardly. with relation to 'the' pivotal point 23. These adjustmentsare usually madein the factory when the instrument is being tested andoncethe adjustment as been properly made further attentfions'jnotrequired; hence the importance of cnploying an exterior adj ustment`if it is nec- Sary to change the position ofthe indicatmlg 'j l l l l.al The sp1ndle'2 0 1s provided `with anfordinary hair spring 'in themanner of all stand:

hand 26withrelat1on-to the: graduated 'di 1 46; this being secured atone end to the casor playin the bearings or connections otherwiseemployed, for instance, the pivotal connections between thel link 25 andthe connections 13vand 15, 'is taken up by a spring ing and at itsopposite endto the adjustable lever 24. This spring exerts a constantpull in the direction ofvarrow a. This pull takes up any slack in theconnections of the link 25 and it tends to swing the main operatinglever about its pivot 15 in the direction lof arrow b. As this yis theease the lever exerts a downward pressure on the bearing 15 land thepivotal connection 13 and as such takes up any lost motion or play thatmayexist'. It further exerts la downward pressure on the plunger 12 andthe rod 11 and maintains these members in constant and intimate contactwith relation to each other and also with relation to the plug 10. j

In actual practice the instrument has been 4employed for numerouspurposes, such as taking stack temperatures, baking. oven temperatures,lead bath temperatures, exhaust gas temperatures of internal.,combustion engines, etc. Tn any of these instances the tubular extension5 vis exteriorally threaded, as 'indicatedy at 5, and as such serves thefunction of forming a connection between the instrument and thesmokestack, bake oven exhaust manifold, or Awhatever the case may be.Ify the instrument .is inserted in the exhaust'manifold of an internalcombustion motor or engine thetube 9, con# taining the rod 11, willextend into the mani#4 fold and the hot exhausting gases will imypingethereon. The tube 9 is econstructed of -a material having acomparatively high coeilicientv of -expansion while the rod 11- isconstructed of a material having an exist-.-

ing low coeiiicient of expansion. Hence when the tube 9 is subjected togases of high temperature, it tends to expand longitudif nally'and` asthe rod 11 d'oes not tend to expand it will settle downwardly in thetube 9, the. plunger 12- will move downwardly.

with the iod 11 and the main operating lever 14 will'- swing about itspivotyl in the direction of arrow b. Link 25.will also move in'the samedirection and the segment' 22 willswingv about its pivot 23 towaids theright, thus .transmitting a. rotary movement to' the .spindle 20, thepinion 21 and the indicating hand 26'in a clockwise direction. The

' amount of movement imparted dependsventirely `upon the temperature'towhich the tube 9 `is exposed, or, in other words,..to`.

the amount of expansion which takes place in the tube.

If the temperature of the gases decreases the tube will contract orshorten, thus forciing the rod 11? and the plunger '12 upwaraiy.

During contra-cloclwise movement of the indicating hand kthe spring 46is extended 'and' lduring al clockwise1 movement of the indicating handthe spring is contracted. The spring, however, always remains undertension so that a sufficient pull is exerted at' all 'times to take upall play, back lash and 'lost motion. This is exceedingly important ascorrect temperature readings could not otherwise be` obtained.

It hasbeen vstated in the preamble to the specification that temperatureindicating -instruments constructed along the lines specified `have beenconstructed and used, but had, practically speaking,l been abandoned fornumerous reasons, among them being deterioration, disintegration andchange in expanding and non-expanding elements by which the. instrumentswere' actuated'.

I have discovered that if the tube 9 is'- constructed of Monel metal andthe rod 11 ofa fused'slag or quartz a dependable-uniform operation canbe secured as, Monel metal will stand high temperatures withoutoxidizing and without affecting the coeflicient of expansion of theMonel metal; this being also true as far as fused slag or quartz rodsare concerned, and it is accordingly im portant that these twospecifiedelements be employed, to-wit, Monel metal and quartz rods, as they arethe only two elements I have so far discovered which are positivelydependable. The tubular extension 5 and the plunger 12 may be made ofany suitable metal as they .are not subjected to high temperatures.However, it is essential that they be made of the same metal so thatthey will both simultaneously contract and expand at a uniform ratio., v

It is also more or less important that the same metals be employedwithin the casing v so lthatsJ uniform expansion of contraction ratlo 1smaintained as all the members are i lunder certain conditionsf'subjectedmore or less conductedV -or radiant heat. It often happens thatinstruments of this character are subjected to abuse. For instance, thetube 9 may be subjected to higher 14 and thesegment 22. That is, thesegment will swinga'bout the pivot 23 to such an extent that the teethon the segment will move out of mesh or engagement with teeth on thepinion 21.- The hair spring cooperating with the pinion will in thatcase un-1 wind and the indicating hand 26 will lose its adjustment. Toprevent disengagement of the pinion and the segment 22 a stop lug 60 is'employed. This. lug moves into engagement with the upper post 19 of thegauge movement and thereby limits the movement of the main operating arm1 4 and the segment 22.l In other words, the mo-v ment the end of thesegment reaches the pinion 22 lug 60 engages the post 19, and. furthermovement or disengagementlof the se ment and pinion is prevented.

Ato,

'main operating lever pivo ing, a link pivotally secured to the adjustafble extension on the gear segment, an`ad,

a casing having .a graduated temperature' indicating dial mountedthereon, a base plate mountedv within the casing, a top plate, a'spindle journalled between the plates and having a gear'pinion mountedthereon, a gear segment pivoted between the plates and interineshingwith the pinion, an adjustable lever extension' on said gear segment, a

main operating lever pivoted within the casing, a link plvotally securedto the adjusta- ,y ble extension on the gear segment, an adj ustableconnection between the opposite end of' the link and the mainoperatinglever,

means for imparting movement to the main4 operating lever, and a springconnected atone end with the casing and at the opposite end with theadjustable extension on the gear segment. v n l 2. In a device of thecharacter described, a casing having a graduated temperature indicatingdial mounted thereon, a base plate mounted withinithe casing, a topplate, a

spindle-journalled between the. plates and havinga gear pinion mounted.thereon, a

gear segment pivotedbetween the plates and intel-meshing with thepinion, an adjusta ble lever-extension-on said ear segment, a

within the casj ustable connection between theopposite end of the linkand themain operatm lever, means for imparting movement to e mainoperating lever, avspring connected at one end with the casing and atthe opposite end with the adjustable extension on the gear segment, andmeans -for limiting pivotal movement of the gear segment to prevent thegear segment from swinging outl of mesh with the pinion. k'

3. In a device of the character described, a casing having a graduatedtemperature indicating dial mounted thereon, a base plate mounted withinthe; casing, a top plate, a spindle journalled between the plates andhaving a gear pinion mounted thereon, a gear segment pivoted between theplates and inter-meshing with the pinion, an adjustable lever extensionvon said gear se ment, a vmain operating lever pivoted within thecasing, a link pivtally secured to the adjustable extension on the gearsegment, an adjustable connection between the opposite endv of the linkand the main operating lever, means for imparting movement to the mainoperating lever, a spring connected at Aone end with the casing and atthe'opposite end with the adjustable extension on the gear segment, anda stop lug mounted on the main operating lever to limit the movement 0Ithe main operating leverV and the gear' segment.`

4. In a device of the. character described, i Y

a casing having a graduated temperature indicating dial mounted thereon,a lbase plate mounted vwithin the casing, a top plate, a spindlejournalled between the plates and having a gear pinion mounted thereon,a gear segment pivoted betweenthe plates and intermeshing with thepinion, an adjustable lever extension on said gear segment, a mainoperating lever pivoted within the. casin av link pivotally secured tothe adjustab e extension on thegear segment, an adjustable connectionbetween the opposite end of the link andthe main operating levfer, meansfor imparting movement to the main operatmg lever, a spring connected at,one end with the casing and at the'opposite end with the-adjustableextension on the gear segment, a pivotal connection between the baseplate and the casing' at a point adjacent the spindle, and an adjustableconnection between the opposite end of the base plate and the casing topermit swinging movement of the base plate about the pivotal connection.f Y

, 5:'In 'a device'ofthe character described,

-a casing having a graduated dial mounted thereon, a. gaugemovementwithin the casing, 'a pointer.v carried bythe gauge movement andlmovable over the dial, a pivotal connection between one end ofthe gau emovement andthe casing, and an. ad'ustaleL connection betweenptheopposite en of the i gauge movement andthe casingv to permit swinging ofthe pivotal connection.

gaugeV movement about thesf ing, a pointer carried by the gauge movementand movable over the dial, av pivotal connection between one end 'of thegauge movement and the casing, an adjustable connection between. theyopposite end of the gauge movement and the caslng to permit swingingof' the gauge movement about the pivotal connection, said adjustableconnection comprising a bolt extendin through a slot in the casing, apost throng which the bolt passes, a second post, a threaded rodconnected with the first named post and extending through the secondnamed post, and adjusting screws mounted on the rod on opposite sidesot' the second named post.

7 In a device of the character described, a tube constructed ofexpansible material, a casing to which the tube is attached, a seat inone end of the tube having a semi-spherical depression formed therein, arod of sub stantially non-expanding material engaging the seat andsupported thereby, the end of the rod being rounded to engage thedepressed seat, a plunger engaging the opposite, end of the rod, arounded depressed seat in the plunger, and a rounded end on the rod toenter the seat. 4

c ROBERT C. PALRMAN.

